Fix #1537721: add writeheader() method to csv.DictWriter.

Reviewed by skip.montanaro and thomas.wouters.

1 files changed, 4 insertions, 0 deletions

diff --git a/Lib/csv.py b/Lib/csv.py
index 3db5dac..1df5062 100644
--- a/Lib/csv.py
+++ b/Lib/csv.py
@@ -132,6 +132,10 @@ class DictWriter:
         self.extrasaction = extrasaction
         self.writer = writer(f, dialect, *args, **kwds)
 
+    def writeheader(self):
+        header = dict(zip(self.fieldnames, self.fieldnames))
+        self.writerow(header)
+
     def _dict_to_list(self, rowdict):
         if self.extrasaction == "raise":
             wrong_fields = [k for k in rowdict if k not in self.fieldnames]